<html>
  <head>
    <style>
      .main {
        border: 10px solid black;
      }
      div.main {
        border: 50px solid black;
      }
    </style>
  </head>
  <body>
    <div class="main">
      test
    </div>
    <div>
     adfasdf
    </div>
  </body>
</html>
